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Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.
Did you know?
HIV testing reach is still limited. An estimated 40% of people with HIV (more than 14 million) remain undiagnosed and do not know their infection status.
Did you know?
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
Did you know?
The modern decimal position system was the invention of the Hindus (around 800 AD), involving the placing of numerals to indicate their value (units, tens, hundreds, and so on).